cpu/nrf/radio/nrfmin: request HFXO clock source
cpu/nrf/radio/nrfmin: request HFXO clock source

RIOT-OS/RIOT,ant9000/RIOT,kaspar030/RIOT,authmillenon/RIOT,kaspar030/RIOT,OlegHahm/RIOT,OTAkeys/RIOT,kaspar030/RIOT,RIOT-OS/RIOT,kaspar030/RIOT,OlegHahm/RIOT,jasonatran/RIOT,OTAkeys/RIOT,authmillenon/RIOT,miri64/RIOT,OlegHahm/RIOT,RIOT-OS/RIOT,jasonatran/RIOT,ant9000/RIOT,OlegHahm/RIOT,kYc0o/RIOT,OTAkeys/RIOT,ant9000/RIOT,OTAkeys/RIOT,authmillenon/RIOT,jasonatran/RIOT,OTAkeys/RIOT,miri64/RIOT,kaspar030/RIOT,miri64/RIOT,kYc0o/RIOT,jasonatran/RIOT,kYc0o/RIOT,miri64/RIOT,jasonatran/RIOT,RIOT-OS/RIOT,kYc0o/RIOT,miri64/RIOT,kYc0o/RIOT,authmillenon/RIOT,RIOT-OS/RIOT,OlegHahm/RIOT,ant9000/RIOT,ant9000/RIOT,authmillenon/RIOT,authmillenon/RIOT